Exhibit Area 1
(Plaza area)
Welcome Sign [main directory]
How the Bridge Spans the Golden Gate
Bridge Aesthetics - Art Deco on a Grand Scale
Tall and Strong - The Bridge Towers
Steel, Fog, Salt, Rust, and Paint

Exhibit Area 2
(near flagpole)
How the Bridge Vibrates
Foghorns

Exhibit Area 3
(West side of Bridge near underpass)
Historic Preservation: Lattice Strut Retrofit
Historic Preservation: Isolator Seismic Retrofit

Exhibit Area 4
(inside Battery area)
History: Design and Construction of the Bridge
Suspension Cable Tension vs. Tower Height
Battery Lancaster - Defending the Golden Gate

Exhibit Area 5
(along bike path to lower parking lot)
Bridge Deck Aerodynamics
Bridge Deck Torsional Resistance Retrofit
Wind Speed and Wind Pressure

Exhibit Area 6
(near Pavillion)
LIFETILES: animated construction of the Bridge
Braille / Tactile Model of the Bridge



Project Partners

GGBHTD
Golden Gate Bridge,
Highway and Transporation District



CUREE

Consortium of Universities for Research
in Earthquake Engineering

Main Menu : Exhibit Area 5

Bridge Deck Torsional Resistance Retrofit

RESISTING THE TWISTING

Ever since the modern suspension bridge was invented in the early 1800s, one of the biggest challenges engineers have faced is preventing these flexible structures from moving too much in the wind.

A storm on December 1, 1951, caused the Golden Gate Bridge to twist and vibrate enough to cause some minor damage, so the Bridge was retrofitted from 1953 to 1954. The retrofit added new bracing across the bottom, connecting the two steel trusses that support the roadway deck. This change increased the Bridge's twisting, or torsional, stiffness.

The Shape of the Bridge Deck

Original Bridge Deck Shape

This is a scale model of a 500-foot (152-meter) length of the original deck structure of the Golden Gate Bridge, without the roadway on top. The trusses on the sides, along with the framing on top that supports the roadway, form an upside-down U-shape.

Retrofitted Bridge Deck Shape

This model shows the Bridge deck today. The difference from the original design, shown above, is the addition of bottom bracing. The cross section is a closed shape.

Trusswork under the Bridge deck

Image shows the new bracing that is visible in the bottom level.

All images property of the Golden Gate Bridge, Highway and Transportation District (unless otherwise indicated).

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Last updated: 11.08.12